抗氧化微营养素对缓解蛋鸡热应激的研究

在热应激条件下,于蛋鸡日粮中添加不同水平的Ｖｃ、Ｓｅ、Ｃｕ、Ｚｎ４种抗氧化微营养素（Ｖｃ１０００ｍｇ／ｋｇ、Ｓｅ０．３ｋｇ／ｋｇ、Ｃｕ４０ｍｇ／ｋｇ、Ｚｎ０．５ｍｇ／ｋｇ）,能有效地缓解热应激,提高产蛋率和饲料报酬,同时可改善蛋壳品质。     

饲粮不同维生素 Ｅ水平对鹅生产性能、胴体品质、血清生化指标和生殖激素含量的影响

本试验以 ０～１２周龄肝用型鹅为研究对象,通过探讨饲粮不同维生素 Ｅ水平对青农灰鹅生产性能、胴体品质、血清生化指标和生殖激素含量的影响,确定育雏、育成期鹅维生素 Ｅ的需要量。试验选择 １日龄青农灰鹅 １８０只,随机分为 ６个处理,每个处理 ３个重复,每个重复 １０只。试验鹅饲喂在玉米 －豆粕型饲粮的基础上分别添加 ０（对照组）、５、１０、２０、４０、８０ＩＵ／ｋｇ维生素 Ｅ的饲粮,试验期为 １２周。结果表明：１）与对照组相比,饲粮添加 ４０、８０ＩＵ／ｋｇ维生素 Ｅ可显著提高 ０～４周龄鹅平均日增重和平均日采食量（Ｐ＜０．０５）,饲粮添加 ４０ＩＵ／ｋｇ维生素 Ｅ可显著提高 ５～１２周龄鹅平均日增重和平均日采食量（Ｐ＜０．０５）。２）饲粮添加 ４０、８０ＩＵ／ｋｇ维生素 Ｅ可显著降低 １２周龄鹅胸肌剪切力和失水率（Ｐ＜０．０５）,饲粮添加 ８０ＩＵ／ｋｇ维生素 Ｅ可显著提高 １２周龄鹅半净膛率和胸肌率（Ｐ＜０．０５）。３）提高饲粮维生素 Ｅ水平可显著提高 ４周龄鹅血清尿素氮含量（Ｐ＜０．０５）,显著降低１２周龄鹅血清尿素氮含量（Ｐ＜０．０１）,饲粮添加４０ＩＵ／ｋｇ维生素 Ｅ可显著提高 ４周龄和 １２周龄鹅血清碱性磷酸酶活性（Ｐ＜０．０５）。４）与对照组相比,４０、８０ＩＵ／ｋｇ维生素 Ｅ组１２周龄母鹅血清中雌二醇含量显著升高（Ｐ＜０．０５）,促卵泡素含量显著降低（Ｐ＜０．０５）。２０、４０、８０ＩＵ／ｋｇ维生素 Ｅ组 １２周龄公鹅血清中雌二醇、睾酮含量均显著升高（Ｐ＜０．０５）,促卵泡素含量显著降低（Ｐ＜０．０５）。本研究结论如下：１）维生素 Ｅ对鹅的生产性能、胴体品质、血清中尿酸、尿素氮、生殖激素含量和碱性磷酸酶活性具有一定调控作用;２）根据建立的回归方程确定肝用型鹅饲粮维生素 Ｅ最适添加量为：０～４周龄４２．９８ＩＵ／ｋｇ,５～１２周龄 ３８．９２～４３．４１ＩＵ／ｋｇ;３）根据鹅血清中生殖激素含量的变化确定饲粮维生素 Ｅ最低添加量为２０ＩＵ／ｋｇ。     

抗氧化微营养素对缓解蛋鸡热应激的研究

在热应激条件下,向蛋鸡日粮中添加不同水平的Ｖｃ、Ｓｅ、Ｃｕ、Ｚｎ四种抗氧化微营养素。结果表明,抗氧化微营养素（Ｖｃ１０００ｍｇ／ｋｇ,Ｓｅ０．３ｍｇ／ｋｇ,Ｃｕ４０ｍｇ／ｋｇ,Ｚｎ８５ｍｇ／ｋｇ）能有效缓解热应激,提高产蛋率和饲料报酬,同时改善蛋壳品质。     

硒,维生素E对鸡体脂质过氧化的影响

２１日龄健康肉鸡８０只,随机分为４组（每组２０只）,分别在基础饲料中添加维生素Ｅ（ＶＥ）＋硒（Ｓｅ）、ＶＥ、Ｓｅ和不添加任何物质。ＶＥ添加量为１００ｍｇ／ｋｇ,Ｓｅ添加量为０．５ｍｇ／ｋｇ。试验期为５周。试验结束,立即采取血液、肝脏、胸肌、腿肌样品,分别于２ｈ内和冷藏（２℃）４８ｈ后检测其谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）和超氧化物歧化酶（ＳＯＤ）的活性以及丙二醛（ＭＤＡ）含量。结果表明,添加ＶＥ和／或Ｓｅ的３个试验组肉鸡的ＧＳＨ－Ｐｘ、ＳＯＤ活性均显著高于对照组,ＭＤＡ含量显著低于对照组,提示饲料中添加ＶＥ和／或Ｓｅ,均可增强鸡体的抗氧化效果。ＶＥ和Ｓｅ联用显示明显的协同效应。     

饲粮铜和维生素 Ａ及其互作效应对肉仔鸡生长性能及抗氧化功能的影响

本研究旨在探讨铜和维生素 Ａ及其互作效应对肉仔鸡生长性能及抗氧化功能的影响。试验选用 １日龄艾维茵肉仔鸡 ４４８只，随机分为 ８组，每组 ４个重复，每个重复 １４只鸡。采用４×２（铜 ×维生素 Ａ）完全随机设计，饲粮铜的添加量分别为 ０、８、１５０、２２５ｍｇ／ｋｇ，维生素 Ａ的添加量分别为 １５００、５０００ＩＵ／ｋｇ，分为 ２个生长阶段，前期为 １～４周龄，后期为 ５～７周龄。结果表明：１）高铜（１５０、２２５ｍｇ／ｋｇ）抑制了全期肉仔鸡生长性能，提高了全期血清铜蓝蛋白（Ｃｐ）和后期血清总超氧化物歧化酶（Ｔ ＳＯＤ）活性（Ｐ＜０．０５）。２）５０００ＩＵ／ｋｇ维生素 Ａ组获得较好的生长性能，提高了全期血清 Ｔ ＳＯＤ活性，降低了前期血清 Ｃｐ活性（Ｐ＜０．０５）。３）铜和维生素 Ａ互作效应对前期体增重、血清 Ｃｐ和 Ｔ ＳＯＤ活性及全期料重比有显著影响（Ｐ＜０．０５），且二者间存在互补作用。铜（８ｍｇ／ｋｇ）×维生素 Ａ（５０００ＩＵ／ｋｇ）组与铜（０ｍｇ／ｋｇ）×维生素 Ａ（５０００ＩＵ／ｋｇ）组对前期肉仔鸡获得良好生长性能和提高血清 Ｔ ＳＯＤ活性均有促进作用，但对血清 Ｃｐ活性有显著降低作用（Ｐ＜０．０５）。由此可见，在基础饲粮铜水平为 １６～２３ｍｇ／ｋｇ时，铜的适 宜 添 加 量 为 前 期 ８ｍｇ／ｋｇ，后 期 ０～８ｍｇ／ｋｇ；全 期 维 生 素 Ａ 的 适 宜 添 加 量 为５０００ＩＵ／ｋｇ。     

添加罗维素328W对罗曼父母代蛋种鸡生产性能影响的试验

１　材料与方法试验于１９９９年２月２５日开始,在赤峰市畜牧研究所种鸡场进行。试验选取同一鸡舍２８周龄罗曼父母代蛋种鸡３０７５只,随机分为２组,试验组１５４５只,对照组１５３０只。以统计分析两组的生产性能之间没有差异开始正式试验。试验期间两组饲料的大原料组成完全相同。基础饲粮采用本场多年来所采用的维生素添加水平,每千克饲料维生素含量分别为ＶＡ１４０００ＩＵ,ＶＤ３３０００ＩＵ,ＶＥ１０ｍｇ,ＶＫ３１．０ｍｇ,ＶＢ１１．１ｍｇ,ＶＢ２６．４ｍｇ,ＶＢ６３．５ｍｇ,叶酸０．８ｍｇ,生物素０．０２ｍｇ,…     

产蛋种鸡日粮中不同水平维生素E与有机和无机硒的效果研究

在３×５的两因子试验中,研究了不同添加水平维生素Ｅ（４、１４和２４ｍｇ／ｋｇ）与有机和无机硒（亚硒酸钠０．２０、０．３５和０．５０ｍｇ／ｋｇ,酵母硒０．３５和０．５０ｍｇ／ｋｇ）对褐壳蛋种母鸡在２０～４０周龄阶段生产繁殖性能和有关血液指标的影响。结果表明,产蛋母鸡的采食量、产蛋率、蛋重、产蛋量、饲料转化率和死淘率在３个维生素Ｅ添加水平间无差异;除了添加酵母硒０．５０ｍｇ／ｋｇ组蛋鸡的蛋重和产蛋量显著低于酵母硒０．３５ｍｇ／ｋｇ组以外,其它各项生产性能指标在各硒处理组间差异不明显。维生素Ｅ和硒可增加彼此在血液中的存留;当日粮中只补加维生素Ｅ４ｍｇ／ｋｇ时,将日粮亚硒酸钠硒添加水平由０．２０ｍｇ／ｋｇ提高到０．３５～０．５０ｍｇ／ｋｇ可使血浆α－生育酚含量由０．５０μｇ／ｍｌ上升到接近１．０μｇ／ｍｌ左右。     

猪育种进展及其发展趋势

哺乳母猪日粮含消化能１４．２１ＭＪ／ｋｇ，粗蛋白１６．３～１９．２％（随猪只日增重的不同而调整），赖氨酸０．８２～１．０３％（随猪只日增重的不同而调整）。加拿大提出的最低营养标准为：中猪（２０～６０ｋｇ）（见表３）；哺乳母猪合消化能１４．０００ＭＪ／ｋｇ，粗蛋白１６％，赖氨酸０．８％，钙０．９％，磷０．７％，ＶＡ７ ５００ＩＵ／ｋｇ、ＶＤ７５０ＩＵ／ｋｇ，ＶＥ３５ＩＵ／ｋｇ，胆碱６００ｍｇ／ｋｇ；生物素０．３０ｍｇ／ｋｇ。 猪育种的进展，有赖于遗传理论的创新和育种技术的改进，国际上以遗传学为理论指…     

玉米脱水酒精糟及其可溶物和维生素 Ｅ水平对肥育猪生长性能、胴体和肉品质的影响

本试验旨在研究饲粮中玉米脱水酒精糟及其可溶物（ＤＤＧＳ）和维生素 Ｅ（ＶＥ）水平对肥育猪生长性能、胴体和肉品质的影响。采用 ３×２两因子完全随机试验设计,设 ３个玉米ＤＤＧＳ水平（０、１５％、３０％）和 ２个维生素 Ｅ水平（１０、２１０ｍｇ／ｋｇ）。选取平均体重为（６０±２）ｋｇ的“杜 ×长 ×大”三元杂交肥育猪 ４８头（公母各占 １／２）,按性别、体重随机分为 ６个组,每个组 ８个重复,每个重复 １头猪。试验期为 ４２ｄ。结果表明：１）玉米 ＤＤＧＳ水平对肥育猪平均日增重和料重比无显著影响（Ｐ＞０．０５）,对平均日采食量影响极显著（Ｐ＝０．００６）,维生素 Ｅ水平及玉米 ＤＤＧＳ和维生素 Ｅ的互作对生长性能无显著影响（Ｐ＞０．０５）;２）玉米 ＤＤＧＳ和维生素Ｅ水平及其互作对胴体重、屠宰率、胴体斜长、背膘厚度、板油率和眼肌面积等胴体品质评定指标影响均不显著（Ｐ＞０．０５）,胴体脂肪碘值随饲粮中玉米 ＤＤＧＳ水平的提高而极显著升高（Ｐ＝０．００１）;３）玉米 ＤＤＧＳ水平对肌肉 ｐＨ、肉色、剪切力、滴水损失和大理石评分影响均不显著（Ｐ＞０．０５）,饲粮中添加 ２１０ｍｇ／ｋｇ维生素 Ｅ可显著降低肌肉剪切力和滴水损失（Ｐ＜０．０５）。可见,在肥育猪基础饲粮中添加 １５％ ～３０％玉米 ＤＤＧＳ和 ２１０ｍｇ／ｋｇ维生素 Ｅ对其生长性能、胴体和肉品质无显著负影响。     

美国研究黄鲟养殖

黄鲟为美国濒危品种,为此科研人员进行了养殖黄鲟试验。给黄鲟鱼苗投喂４种干饲料和半湿配合饲料,饲料配方如下：鱼粉６７％、干乳清６％、虾粉６％、维生素１－５％、无机盐０－５％、维生素Ｃ０－１％、营养素１－４％、鱼油１５％、粘合剂２％。维生素每ｋｇ含ＶＡ１００００ＩＵ、ＶＤ３４０００ＩＵ、ＶＫ１０ｍｇ、ＶＥ７８０ＩＵ、维生素Ｂ１４０ｍｇ、ＶＢ２３０ｍｇ、泛酸钙１５０ｍｇ、烟酸１５０ｍｇ、ＶＢ６２０ｍｇ、生物素３ｍｇ、叶酸１５ｍｇ、ＶＢ１２、０－２ｍｇ、喹乙醇１５０ｍｇ、肌醇１０００ｍｇ。鱼苗投喂开食饵…     

Effect of selenium and vitamin E content of the maternal diet on the antioxidant system of the yolk and the developing chick

1. The effects of selenium and vitamin E supplementation of the maternal diet on their transfer to the egg yolk and tissues of the newly hatched chick and on the development of the antioxidant system in the chick liver in early postnatal life were investigated. 2. One hundred Cobb broiler breeder hens were divided into 10 equal groups and housed in pens at 25 weeks of age. Each hen received 1 of the treatment diets which included 0.2 or 0.4 mg/kg selenium, 40, 100, 200 mg/kg vitamin E or their combination. After 6 weeks, the hens were artificially inseminated once per week. From week 8, eggs were collected and placed in an incubator. After hatching, chicks from each group were reared (under standard commercial conditions) to 10 d of age. The chicks were fed on a standard starter commercial broiler diet. At the time of hatching, and at 5 and 10 days old, 4 chicks from each group were sacrificed and blood, liver and brain were collected for the subsequent biochemical analyses. 3. The inclusion of organic selenium or vitamin E in the commercial diet significantly increased their concentration in the egg and in the liver of 1-d-old chicks obtained from the eggs enriched with these substances. A positive effect of such dietary supplementation was seen at d 5 and d 10 of postnatal development. 4. There was a positive effect of selenium supplementation of the maternal diet on glutathione concentration in the liver of 1-d-old and 5-d-old chicks. A combination of a dietary selenium supplementation with high vitamin E doses further increased glutathione concentration in the liver. Dietary selenium supplementation significantly increased selenium-dependent glutathione peroxidase (Se-GSH-Px) activity in the liver of the 1-d-old and 5-d-old chicks and decreased liver susceptibility to peroxidation. 6. It is concluded that the nutritional status of the laying hen determines the efficiency of the antioxidant system throughout embryonic and early postnatal development of the offspring.     

饲粮中添加维生素E和有机硒对攸县麻鸭产蛋性能、蛋品质、血清生化指标及咸蛋蛋黄品质的影响

本试验旨在研究饲粮中添加维生素E和有机硒对攸县麻鸭产蛋性能、蛋品质、血清生化指标及咸蛋蛋黄品质的影响。选用200只健康的处于产蛋高峰期的攸县麻鸭,随机分为4个组,每组5个重复,每个重复10只鸭。对照组(Ⅰ组)饲喂基础饲粮,3个试验组(Ⅱ、Ⅲ、Ⅳ组)分别在基础饲粮中添加50 IU/kg维生素E、0.2 mg/kg硒、0.2 mg/kg硒+50 IU/kg维生素E。试验期为63 d。结果表明：1)Ⅱ、Ⅲ和Ⅳ组的产蛋率和日产蛋重均显著高于对照组(P<0.05)。Ⅱ、Ⅲ和Ⅳ组的料蛋比均显著低于对照组(P<0.05)。2)Ⅲ和Ⅳ组的蛋黄硒含量显著高于对照组(P<0.05)。Ⅱ和Ⅳ组的蛋黄维生素E含量显著高于对照组(P<0.05)。3)Ⅱ、Ⅲ和Ⅳ组的咸蛋蛋黄硬心率显著低于对照组(P<0.05),Ⅳ组硬心率显著低于Ⅱ和Ⅲ组(P<0.05)。4)Ⅱ、Ⅲ和Ⅳ组的血清中丙二醛(MDA)含量显著低于对照组(P<0.05)。Ⅱ、Ⅲ和Ⅳ组的血清中谷胱甘肽(GSH)含量和谷胱甘肽过氧化物酶(GSH-Px)活性均显著高于对照组(P<0.05)。由此可见,饲粮中添加维生...     

Effects of continuous supplementations of ascorbic acid, aspirin, vitamin E and selenium on some haematological parameters and serum superoxide dismutase level in broiler chickens

1. This study was conducted using male broiler chickens to determine the effects of ascorbic acid, aspirin, ascorbic acid+aspirin, vitamin E+selenium and ascorbic acid+aspirin+vitamin E+selenium supplementations on haematological parameters and serum superoxide dismutase concentration. 2. One hundred and twenty day-old male Hubbunt broiler chicks were randomly divided into 6 experimental groups of 20 chicks each and placed in different pens. Groups 2, 3, 4, 5 and 6 were given a diet supplemented with ascorbic acid, aspirin (in water), ascorbic acid+aspirin, vitamin E+selenium and ascorbic acid+aspirin+vitamin E+selenium, respectively for 45 d while group 1 was given a commercial broiler diet. 3. There was no significant effect of ascorbic acid, aspirin, ascorbic acid+aspirin, vitamin E+selenium supplementations on any of the haematological parameters (red blood cell, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin concentration, mean corpuscular haemoglobin) in broilers but ascorbic acid+aspirin+vitamin E+selenium supplementation significantly decreased the white blood cell counts. 4. In addition to this, ascorbic acid, aspirin, ascorbic acid+aspirin and ascorbic acid+aspirin+vitamin E+selenium supplementations had no significant effect on the serum superoxide dismutase level, but vitamin E+selenium supplementation increased the serum superoxide dismutase level.     

The effect of dietary vitamin E level on selenium status in rats

The effect of varying levels of dietary vitamin E on selenium status was determined using 40 Wistar rats with similar initial body weight. The rats were equally divided into four groups and fed the following dietary treatments (mg vitamin E/kg DM): 18 (control; C‐diet), 0 (0E‐diet), 9 (0.5E‐diet) and 36 (2E‐diet) for either 4‐week (Phase 1) or 8‐week (Phase 2) period. At the end of experiment, animals were slaughtered to measure vitamin E and selenium levels in the brain, liver, spleen, kidney, muscles and blood tissues. Dietary vitamin E levels did not affect feed and water intake and body weight. But whole‐blood selenium concentration in rats fed 0E‐diet was higher than in rats fed 2E‐diet after 4 weeks. Selenium level in muscle, spleen and brain was also higher (p < 0.05) in rats fed the 0E‐diet than in rats fed C‐diet after 4 weeks of feeding. On the other hand, selenium level in the muscle was lower (p < 0.05) in rats fed 0.5E‐diet than in those fed 0E‐diet after 4 weeks of feeding, but not after 8 weeks of feeding. Increasing dietary vitamin E level directly influenced selenium content of the spleen and brain after 8 weeks of feeding 2E‐diet. Moreover, the twofold increase in vitamin E intake resulted in a tendency to reduce whole‐blood selenium level and total selenium in the liver and kidney after 4 and 8 weeks. The results showed that the increasing dietary vitamin E level resulted in a tendency to reduce Se contents in some vital organs of the body such as the liver and kidney, suggesting their close compensatory interrelationship. Therefore, dietary vitamin E level directly influenced selenium metabolism in the animal body.     

利用富硒酵母生产富硒鸡蛋的技术研究

 采用短期饲喂试验研究富硒酵母硒在鸡蛋中的沉积。结果显示,在蛋鸡日粮中加入不同浓度的酵母硒(有机硒),短期饲喂即可通过鸡本身的生物转化获得含硒量较高,同时又符合食品卫生标准(GB 2762-2005)中硒限量0.5 mg/kg的鸡蛋,且对蛋鸡生产性能无显著影响,对鸡蛋品质也没有不良影响,鸡蛋中的硒主要存在于蛋黄中。     

Vitamin C Overcomes the Detrimental Effect of Vanadium on Brown Eggshell Pigmentation

Phosphorus supplementation from poor quality feed-grade sources may introduce excessive levels of vanadium (V) into the diets of laying hens. Vanadium in the diet of chickens has been shown to be detrimental to egg production, albumen height, BW, and feed consumption. This study showed that dietary V also has a negative effect on the color of brown eggshells from commercial-type layers. Commercial-type brown egg layers were fed a cornsoybean meal basal diet supplemented with 0, 50, or 100 ppm of V as NH₄ VO₃ to determine the effect on shell pigmentation. Hens fed V at both dietary concentrations laid lighter colored eggs (less redness) after only 2 d. Another experimental group of the same type of hens that were fed lower V concentrations (0, 15, or 30 ppm) also had less shell pigmentation. After the detrimental “bleaching” effect on shell color was observed, these diets were supplemented with 1 of the following: no supplement, 100 ppm of vitamin C, 100 IU of vitamin E, or 100 ppm of β-carotene. Only vitamin C restored the eggshell color of eggs from hens fed both levels of V. When these same antioxidants were added as preventive agents to diets supplemented with 15 ppm of V before the effects of V were established, brown layers benefited again from 100 ppm of vitamin C but not from vitamin E or β-carotene.     

Infleuce of dietary levels of vitamin E and selenium on tissue and blood parameters in pigs.

Eighteen barrows approximately three weeks of age were used in a 3 X 3 factorial arrangement to investigate the effect of level of supplemental vitamin E and selenium on tissue and blood parameters. Tissue selenium concentrations increased in a quadratic manner with increased selenium intake with kidney tissue containing considerably greater concentrations than liver, heart or muscle. Supplementation of the diet caused a three-fold increase in serum selenium within the first week with a slight tendency to further increases in subsequent weeks. Serum vitamin E of unsupplemented pigs declined by fifty percent during the experiment, whereas supplemental vitamin E resulted in increased serum vitamin E. There was a considerable viration in percent peroxide hemolysis. Correlation of -0.63 between percent peroxide hemolysis and vitamin E intake and -0.85 between percent peroxide hemolysis and serum vitamin E were observed.     

Influence of high vitamin E dosages on retinol and carotinoid concentration in body tissues and eggs of laying hens.

The aim of the study was to contribute to the discussion of overdosing vitamin E in laying hens. A total of 45 laying hens, divided into 5 groups were fed diets supplemented with either 0; 100; 1000; 10,000 or 20,000 mg dl-alpha-tocopheryl acetate/kg diet over a period of 10 weeks. Concentrations of vitamins A and E were measured in plasma, various tissues and egg yolk. Furthermore egg yolk colour and some carotinoids were measured in egg yolks. None of the vitamin E doses significantly influenced performance of the hens. As expected, vitamin E concentration in plasma, all tissue samples and egg yolk was significantly increased with increasing tocopherol content in the diet. The egg yolk showed the highest vitamin E concentration, followed by liver and muscles. Feeding 1000 mg alpha-tocopheryl acetate per kg diet resulted in an increase of vitamin A concentration in the liver. Very high doses (10,000 and 20,000 mg/kg diet) significantly decreased retinol concentration in the liver and egg yolk, as well as carotinoid concentration in the egg yolk. The lower carotinoid concentration in egg yolk resulted in a decreased intensity of egg yolk colour. A prooxidative and/or competitive effect of very high doses of vitamin E with other fat soluble substances has been discussed.     

Effect of dietary supplementation with vitamins E and C on production performance, immune responses and antioxidant status of White Leghorn layers under tropical summer conditions

1. The effects of vitamin E (DL-alpha-tocopheryl acetate) and vitamin C (ascorbic acid) supplementation on performance, some immune variables and antioxidant status of White Leghorn layers (aged 44-56 weeks) exposed to tropical summer conditions were investigated. 2. Both vitamins E and C significantly improved the egg production, food conversion efficiency, antibody responses to inoculated sheep red blood cells (SRBC) and Newcastle disease virus (NDV) vaccine, lymphocyte proliferation in response to mitogen and activities of antioxidant enzymes red blood cell catalase (RBCC) and glutathione peroxidase (GSH-PX) in layers. Vitamin C increased the inflammatory response to phytohaemagglutinin-P (PHA-P) inoculation. 3. Supplemental vitamin C at 200 mg/kg diet significantly increased eggshell weight, eggshell thickness, and shell breaking strength. However, no effect of supplemental vitamin E on eggshell quality was observed. 4. Vitamins E and C, as well as interactions between them, significantly influenced the activities of glutathione reductase and lipid peroxidase. A combination of vitamin E at 125 IU/kg with vitamin C at 200 mg/kg diet had an additive effect on reducing the activity of oxidative enzyme lipid peroxidase (LP) and increasing the activity of antioxidant enzyme glutathione reductase (GSHR). 5. It is concluded that vitamin E (125 IU/kg) and vitamin C (200 mg/kg) could independently alleviate the effects of heat stress on production performance and immunological variables of layers. However, combination of both the vitamins at the above-mentioned concentrations is beneficial in eliciting higher antioxidant status in laying hens exposed to tropical summer conditions.